Generalized Lymph Node Activation after Influenza Vaccination on F FDG-PET/CT Imaging, an Important Pitfall in PET Interpretation.

We report on a 59-year-old female patient with an infected vascular graft investigated with F FDG-PET/CT. The first of two studies showed FDG activity in the left deltoid and ipsilateral axillary lymph nodes explained by influenza vaccination the day prior. The second F FDG-PET/CT showed multiple FDG-avid lymph nodes on both sides of the diaphragm without tracer accumulation at the vaccination site.